Posterior condylar offset does not correlate with knee flexion after TKA.

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Radiology

Background:

• Conflicting evidence exists regarding the influence of posterior condylar offset on knee flexion post-total knee arthroplasty (TKA).
• Understanding this relationship is crucial for optimizing TKA outcomes and implant design.

Purpose of the Study:

• To investigate the correlation between posterior condylar offset and knee flexion angle one year after TKA.
• To compare this correlation in both posterior cruciate ligament (PCL)-retaining and PCL-substituting TKA implants.

Main Methods:

• A quasirandomized study involving 170 patients undergoing primary TKA.
• Patients received either a PCL-retaining (85 knees) or PCL-substituting (85 knees) prosthesis.
• Quantitative 3D CT analysis was used to measure medial and lateral posterior condylar offsets and knee flexion angles preoperatively and at 12 months postoperatively.

Main Results:

• No significant correlation was found between posterior condylar offset and knee flexion at one year in PCL-retaining knees.
• Similarly, no significant correlation was observed in PCL-substituting knees.
• Mean postoperative changes in knee flexion were -5° ± 15° for PCL-retaining and -2° ± 18° for PCL-substituting TKA.

Conclusions:

• Individual posterior condylar offset differences do not correlate with knee flexion changes one year after TKA with current PCL-retaining or PCL-substituting prostheses.
• Accurate assessment of which condyle influences TKA outcomes may be challenging with conventional radiographic techniques.